About the demo I made yesterday

Dear all,

During the call yesterday I made a demo about how in the ITEA2 SEAS project
we deal with modularized and versioned ontologies.
I used https://w3id.org/seas/ to show some of the best practices we use,
and https://w3id.org/seas/SSNAlignment to show how we expose the alignments
in a separate ontology module (aka file).

The purpose of this mail is to propose to adopt two best practices within
this group:

1) add Content-Disposition headers.
When I issue a HTTP GET at http://w3id.org/seas/SystemOntology and request
for application/rdf+xml, my browser downloads a file named
"SystemOntology-1.0.rdf". If I do the same:
 - at http://purl.oclc.org/NET/ssnx/ssn#, I get just "ssn";
 - at http://www.w3.org/ns/ssn/, I get "téléchargement" (French for
download)
How it works: the name for the file is suggested to the browser using HTTP
header Content-Disposition (RFC 6266).
Proposal: add the following header when serving one of the modules in SSN
 - Serving a Turtle representation:
Content-Disposition: filename= ssn-<name of the module>.ttl;
 - Serving a RDF/XML representation,
Content-Disposition: filename= ssn-<name of the module>.rdf;

Note: the file extension for application/rdf+xml, as registered at the
IANA, is ".rdf".
people sometimes use extensions ".owl". this comes from the old OWL
recommendation [2] which does not use the proper IANA registration form.
OWL2 defines more media types for OWL: the XML serialization media type
application/owl+xml, with file extension ".owx" [3], there is also one for
the functional syntax and the manchester syntax.
Yet, these media types don't seem to ever have been registered to the IANA
[4].

2) use proper 303 redirection
When I issue a HTTP GET at https://w3id.org/seas/System, I do not directly
get a 200 OK HTTP status code. I first get a 302 Found (because of w3id),
then a 303 See Other that actually redirects me to the IRI of the latest
version of the ontology module that defines this concept:
https://w3id.org/seas/SystemOntology-1.0
If I do the same at https://www.w3.org/ns/ssn/Sensor, I just a 200 OK.
Why we might want to use a 303 redirect: because there are two solutions
for Cool URIs for the Semantic Web [5]: hash URIs, and 303 URIs. By
choosing slash-based URIs, we should let them be 303 URIs.

Kind regards,
Maxime

[1] http://www.iana.org/assignments/media-types/application/rdf+xml
[2] https://www.w3.org/TR/owl-ref/#MIMEType
[3] *https://www.w3.org/TR/owl2-xml-serialization/#Appendix:_Internet_Media_Type.2C_File_Extension.2C_and_Macintosh_File_Type
<https://www.w3.org/TR/owl2-xml-serialization/#Appendix:_Internet_Media_Type.2C_File_Extension.2C_and_Macintosh_File_Type>*
[4] http://www.iana.org/assignments/media-types/media-types.xhtml
[5] https://www.w3.org/TR/cooluris/#solutions